1. Field of the Invention
The present invention relates generally to a nozzle. More particularly, the present invention relates to a vacuum nozzle for a pick and place machine.
2. Discussion of Related Arts
In the discussion of the related art that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art against the present invention, if appropriate.
Vacuum transfer systems, so-called xe2x80x9cpick and placexe2x80x9d systems, have various uses. For example, a vacuum transfer system can be utilized to transfer components from a first station to a second station, such as in an assembly line or packaging process, or to manipulate components in a manufacturing environment, such as in the microelectronics industry.
In a vacuum transfer system, the nozzle piece physically touches the objects that are manipulated, e.g., the nozzle is manipulated to contact an object, forms a vacuum seal with the object, and then is manipulated to transfer the object to a second location. Both vacuum transfer system efficiency and component throughput can be improved by increasing the rate of transfer of the objects. However, an increase in the transfer rate is accompanied by an increase in the operating speed of the vacuum transfer system. Accordingly, an increase in the speed increases the contact velocity of the nozzle to the object. In one application, the object to be transferred is an integrated circuit, known in the industry as a die or a die chip.
Nozzles for vacuum transfer systems have previously been one continuous piece from the connection point with the vacuum transfer system to the tip, i.e., of unitary design. Such nozzles create impact forces arising from kinetic energy, with the impact forces varying proportionably to the mass and velocity following the kinetic energy formula, KE=xc2xd mv2. Higher velocities can produce a higher impact force on the object with attendant failure rates and/or breakage of the object. Also, the pick efficiency, i.e., the success rate of the vacuum transfer system at picking up a component part.
Thus, in the above described vacuum transfer process and in similar processes, it is desirable to increase the vacuum transfer rate and object throughput while also minimizing the forces applied to the object and thereby minimize the undesirable effects of an increase speed, e.g., decrease the failure rate and incidence of breakage.
The present invention provides a vacuum nozzle for a vacuum transfer system. In an exemplary embodiment, the nozzle comprises a nozzle body and a nozzle tip that are joined to allow relative movement therebetween. The nozzle body has a body passage extending axially therethrough from a first end to a second end. The nozzle tip includes a tip passage extending axially therethrough and is in operative communication with the body passage to port a vacuum to a distal portion of the nozzle tip. The nozzle tip includes a proximal portion and a distal portion, and is adapted at a distal end to contact a component to be manipulated. The proximal portion of the nozzle tip is adapted to slidably engage in the axial direction within the body passage of the nozzle body. The relative movement of the nozzle tip isolates the momentum contribution from the nozzle body as far as contributing to the force of impact of the vacuum nozzle with the component to be manipulated.
In a further exemplary embodiment, the nozzle comprises a nozzle body, a nozzle tip joined to the nozzle body to allow relative movement therebetween, and a compliant element. The compliant element is disposed between a seating surface of the nozzle tip and the second end of the nozzle body. The compliant element absorbs a portion of the impact forces associated with the momentum of the vacuum nozzle as the nozzle tip contacts a component to be manipulated. Further, the compliant element forms a vacuum seal between the nozzle body and the nozzle tip.
In an exemplary embodiment, the proximal portion of the nozzle tip slides telescopically within the body passage of the nozzle body. In an additional exemplary embodiment, the nozzle body includes a portion that slides telescopically within an interior portion of the nozzle tip.
In further exemplary embodiments, the body passage has a first radial dimension at a first portion and a second radial dimension at a second portion, the first radial dimension is greater than the second radial dimension. A shoulder is formed at the intersection of the first radial dimension and the second radial dimension. The proximal portion of the nozzle tip includes at least one flexible arm and an interfacing element disposed thereon, which protrudes radially outward to a radial dimension greater than the second radial dimension. The flexible arm elastically bends to allow the protruding interfacing element to slidably pass through the second portion. The interfacing element cooperatively engages with the shoulder in the nozzle body to provide a mounting feature.
Impact forces in a vacuum transfer system having a nozzle can be reduced by forming the nozzle in at least two parts. In an exemplary method of using a vacuum nozzle with a vacuum transfer system to manipulate components and to reduce impact forces, a vacuum nozzle is placed in fluid communication with a supply line in a vacuum transfer system. The vacuum transfer system is maneuvered to engage the vacuum nozzle with a component, which is then manipulated. The first part of the nozzle comprises a nozzle body adapted to attach to a supply line of the vacuum transfer system and the second part comprises a nozzle tip adapted to contact a component to be manipulated. A proximal portion of the nozzle tip is slidably engaged with the body passage of the nozzle body. Further, the proximal portion comprises at least one flexible arm and an interfacing element disposed thereon and the interfacing element cooperatively engages with a receiving element associated with the nozzle body to provide a mounting feature. By forming the nozzle in at least the two parts, the unsprung mass of the nozzle is reduced with attendant reduction in force transferred to a component when the nozzle contacts the component. Further, the vacuum nozzle can be assembled with the first part joined to the second part with a compliant element disposed therebetween.
In a further exemplary embodiment, a vacuum nozzle for a vacuum transfer system is used to manipulate components and to reduce impact forces thereon. A vacuum nozzle is positioned with respect to the object and the nozzle tip contacts the object which is then manipulated. The vacuum nozzle comprises a nozzle body and a nozzle tip joined to the nozzle body to allow relative movement therebetween. Therefore, the force of impact between the nozzle tip and the object is substantially based only on the momentum arising from the mass of the nozzle tip.